I love RPGs mostly like Final Fantasy,Kingdom Hearts,and Pokemon are my favorites.
I would recommend Kingdom Hearts it's my favorite game.I have just started Twilight Princess on Wii and would recommend it.I don't have a PSP but Final Fantasy Tactics-lion wars is out for it and have heard good things about it.
Castlevania Drancula X is out for PSP also and have heard that when you beat the main game,you unlock another game form the castlevania series.